1. Field of the Invention
The present invention relates to a personal computer using a replaceable hard disk as an external storage medium.
2. Description of the Related Art
In the field of personal computers in recent years, compact, lightweight, portable laptop personal computers have been very popular in place of conventional desk-top personal computers. Demand has increasingly arisen for more compact, lightweight, portable laptop personal computers. The most advanced laptop personal computer employs a low-profile floppy disk drive (FDD), and a display and a hard disk pack are detachably mounted in this personal computer.
In order to improve user operability, a laptop personal computer has a resume mode as a standard mode. In the resume mode, a state (i.e., a content of a memory and contents of various types of register) in the system is saved in a nonvolatile memory in a power-OFF state, and a state immediately before the power-OFF timing is restored upon power-ON. Therefore, Jobs can be continued regardless of a power-ON/OFF state.
A hard disk pack is generally replaced in a power-OFF state to prevent attachment/detachment of the hard disk pack while signal lines are kept active. In the above personal computer, however, if a hard disk pack is detachable and when it is replaced in a power-OFF state, a change in content of the hard disk pack is not detected and a Job is resumed in a resume mode. Therefore, the content of the hard disk pack is broken, and a system may overrun.